COMPARATIVE BIOCHEMICAL-STUDIES ON F AND EDP208 CONJUGATIVE PILI
COMPARATIVE BIOCHEMICAL-STUDIES ON F AND EDP208 CONJUGATIVE PILI
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DOI：
10.1128/jb.141.1.333-341.1980
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发表时间：
1980-01-01
影响因子：
3.2
通讯作者：
PARANCHYCH, W
中科院分区：
文献类型：
--
作者：
ARMSTRONG, GD;FROST, LS;PARANCHYCH, W
EDP208菌毛由一种自然产生的Lac质粒Folac(不相容组Fv)的去压衍生物编码，Folac最初是从伤寒沙门氏菌中分离出来的。EDP208菌毛在血清学上与F菌毛无关，并且不促进F-特异性RNA噬菌体的感染。它们赋予了对F-特异的丝状DNA噬菌体的敏感性。含有EDP208的细胞具多毛，每细胞含有约20个菌毛。这些菌毛含有一个11,500道尔顿的多肽亚基。EPD208特异性RNA噬菌体可以很容易地从当地污水中分离出来。这些噬菌体的直径比F-特异性RNA噬菌体稍小，对EDP208菌毛的吸收相对较弱。比较EDP208和F，两者都含有相当于2-3个己糖单位/亚单位和封闭的N-末端。EDP208菌毛蛋白含有1个共价连接的磷酸残基/亚基，而F菌毛蛋白亚基含有2个这样的残基。虽然在3个或4个氨基酸的情况下发现了显著的差异，但F和EDP208的总体氨基酸组成非常相似。这两种蛋白的胰酶肽谱包含7个具有相似迁移率的多肽，表明它们的氨基酸序列具有相当的同源性。在圆二色谱研究的基础上，F和EDP208的二级结构也有很大的相似性。两种蛋白质的α-螺旋含量均为65-70%。X-射线纤维衍射研究表明，F和EDP208菌毛的亚基排列也很相似。结果表明，F和EDP208菌毛是紧密相关的结构。
EDP208 pili are encoded by a derepressed derivative of a naturally occurring lac plasmid, Folac (incompatibility group FV), originally isolated from Salmonella typhi. EDP208 pili are serologically unrelated to F pili and do not promote infection by F-specific RNA bacteriophages. They confer sensitivity to the F-specific filamentous DNA phages. EDP208-containing cells are multi-piliated and contain approximately 20 pili/cell. These pili contain a single polypeptide subunit of 11,500 daltons. EPD208-specific RNA phages were readily isolated from local sewage. These phages were somewhat smaller in diameter than the F-specific RNA phages and absorbed relatively weakly to EDP208 pili. Comparing EDP208 pilin to F, both contain the equivalent of 2-3 hexose units/subunit and blocked N-termini. EDP208 pilin contains 1 covalently linked phosphate residue/subunit, whereas the F pilin subunit contains 2 such residues. Although notable differences were found in the case of 3 or 4 amino acids, the overall amino acid compositions of F and EDP208 were very similar. The tryptic peptide maps of the 2 proteins contained 7 peptides with similar mobilities, suggesting considerable homology in their amino acid sequences. Substantial similarities were also noted in the secondary structures of F and EDP208 pilin on the basis of circular dichroism studies. The .alpha.-helix content of both proteins was 65-70%. X-ray fiber diffraction studies have indicated that the arrangements of subunits in F and EDP208 pili are also similar. It was concluded that F and EDP208 pili are closely related structures.